Urbanization degree rather than methanotrophic abundance decreases soil CH4 uptake

Abstract

Urbanization has been increasing worldwide, which can greatly influence ecosystem functions such as soil methane (CH4) uptake. However, little information is available for quantifying the effects of urbanization on soil CH4 uptake and the underlying microbial mechanisms. By conducting a meta-analysis of soil CH4 uptake under urbanization worldwide in combination with measurements of potential soil CH4 uptake from 134 samples along an urbanization gradient across Shanghai, China, we found that urbanization significantly decreased soil CH4 uptake with greater inhibition under higher urbanization levels. Urbanization degree, index of urbanization levels, explained large variations of soil CH4 uptake, and urbanization decoupled the relationships between methanotrophic abundance and soil CH4 uptake, which was often neglected in previous research. To our knowledge, this is the first study to quantify the effects of urbanization degree on soil CH4 uptake, which need to be incorporated into Earth system models for estimating the global CH4 budget more accurately.